Display devices such as liquid crystal displays and organic electroluminescence (EL) display devices comprise various wiring lines including gate lines, source lines, etc. which are connected to switching elements and the like, which drive pixels.
In recent years, as the definition of the display device is improved, the number of wiring lines such as gate lines and source lines is increasing. On the other hand, for displaying moving images, for example, pixels are sometimes driven at a high frequency of about 120 Hz. For this reason, in order to achieve both a high definition and a high driving frequency, it is necessary to write signals in many wiring lines at high frequency, which creates a tendency of shortening the signal write-in time.
Moreover, in order to suppress the decrease in the aperture ratio, which may be caused by the wiring lines the number of which is increasing, the width of the lines is reduced, which also creates a tendency of increasing the electric resistance of the wiring lines.
Thus, signals need to be written in the wiring lines of high resistance in a short time, and therefore it is difficult to write a signal to each line normally, which may cause degradation in display quality.